* [PATCH v9 15/20] coresight: Control path during CPU idle
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Control links and helpers on an active path during CPU idle.
Retrieves the per-CPU path pointer. Since the path pointer is only set
via an SMP call on the local CPU, which is serialized with CPU PM
notifiers. If the CPU PM notifier retrieves a non-NULL path pointer, it
is safe to iterate over the path and control it up to the node before
the sink to avoid latency.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index c0f76ea7857e2bf368f9e5abbb023d7a34b4caf5..7fafec04de3e8262b7ca66671c6de635b671ceba 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1768,13 +1768,32 @@ static void coresight_pm_device_restore(struct coresight_device *csdev)
static int coresight_pm_save(struct coresight_path *path)
{
struct coresight_device *source = coresight_get_source(path);
+ struct coresight_node *from, *to;
+ int ret;
+
+ ret = coresight_pm_device_save(source);
+ if (ret)
+ return ret;
- return coresight_pm_device_save(source);
+ from = coresight_path_first_node(path);
+ /* Up to the node before sink to avoid latency */
+ to = list_prev_entry(coresight_path_last_node(path), link);
+ coresight_disable_path_from_to(path, from, to);
+
+ return 0;
}
static void coresight_pm_restore(struct coresight_path *path)
{
struct coresight_device *source = coresight_get_source(path);
+ struct coresight_node *from, *to;
+
+ from = coresight_path_first_node(path);
+ /* Up to the node before sink to avoid latency */
+ to = list_prev_entry(coresight_path_last_node(path), link);
+ if (coresight_enable_path_from_to(path, coresight_get_mode(source),
+ from, to))
+ return;
coresight_pm_device_restore(source);
}
--
2.34.1
^ permalink raw reply related
* [PATCH v9 14/20] coresight: Introduce coresight_enable_source() helper
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Introduce the coresight_enable_source() helper for enabling source
device.
Add validation to ensure the device is a source before proceeding with
further operations.
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 18 ++++++++++++++++--
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
drivers/hwtracing/coresight/coresight-priv.h | 3 +++
drivers/hwtracing/coresight/coresight-sysfs.c | 2 +-
4 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index ae0ab074293a8ec473de2e6e3282f62268de38aa..c0f76ea7857e2bf368f9e5abbb023d7a34b4caf5 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -411,11 +411,25 @@ static void coresight_disable_helpers(struct coresight_device *csdev,
}
/*
- * coresight_disable_source() only disables the source, but do nothing for
- * the associated helpers, which are controlled as part of the path.
+ * coresight_enable_source() and coresight_disable_source() only enable and
+ * disable the source, but do nothing for the associated helpers, which are
+ * controlled as part of the path.
*/
+int coresight_enable_source(struct coresight_device *csdev,
+ struct perf_event *event, enum cs_mode mode,
+ struct coresight_path *path)
+{
+ if (!coresight_is_device_source(csdev))
+ return -EINVAL;
+
+ return source_ops(csdev)->enable(csdev, event, mode, path);
+}
+
void coresight_disable_source(struct coresight_device *csdev, void *data)
{
+ if (!coresight_is_device_source(csdev))
+ return;
+
source_ops(csdev)->disable(csdev, data);
}
EXPORT_SYMBOL_GPL(coresight_disable_source);
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index cae6738e9906c35d291e4b0f3feae37306b95c06..b23c8c4b87972ed530743ef93bea69544c2c5ebf 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -533,7 +533,7 @@ static void etm_event_start(struct perf_event *event, int flags)
goto fail_end_stop;
/* Finally enable the tracer */
- if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF, path))
+ if (coresight_enable_source(csdev, event, CS_MODE_PERF, path))
goto fail_disable_path;
/*
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index ff8a720339deb854ac3b4eb916f49e844f442d34..43ce810ad5deab339f0a336266b6018ddaf8c4fd 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -248,6 +248,9 @@ void coresight_add_helper(struct coresight_device *csdev,
void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
struct coresight_device *coresight_get_percpu_sink(int cpu);
+int coresight_enable_source(struct coresight_device *csdev,
+ struct perf_event *event, enum cs_mode mode,
+ struct coresight_path *path);
void coresight_disable_source(struct coresight_device *csdev, void *data);
void coresight_pause_source(struct coresight_device *csdev);
int coresight_resume_source(struct coresight_device *csdev);
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index f398dbfbcb8de0c5a873837c19b3fdcf97b64abe..9449de66ba3941614928924086100866f3c88a54 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -66,7 +66,7 @@ static int coresight_enable_source_sysfs(struct coresight_device *csdev,
*/
lockdep_assert_held(&coresight_mutex);
if (coresight_get_mode(csdev) != CS_MODE_SYSFS) {
- ret = source_ops(csdev)->enable(csdev, NULL, mode, path);
+ ret = coresight_enable_source(csdev, NULL, mode, path);
if (ret)
return ret;
}
--
2.34.1
^ permalink raw reply related
* [PATCH v9 11/20] coresight: Move source helper disabling to coresight_disable_path()
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Move source helper disabling to coresight_disable_path() to pair it with
coresight_enable_path().
In coresight_enable_path(), if enabling a node fails, iterate to the
next node (which is the last successfully enabled node) and pass it to
coresight_disable_path() for rollback. If the failed node is the last
node on the path, no device is actually enabled, so bail out directly.
As a result, coresight_disable_source() only controls the source,
leaving the associated helpers to be managed as part of path. Update
the comment to reflect this change.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 32 ++++++++++++----------------
1 file changed, 14 insertions(+), 18 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 8384d1466b4cc74f7e463388862c58c86b74be79..e9fcb82a2abcd52d23a3bed14ca14823dc49df6b 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -388,19 +388,12 @@ static void coresight_disable_helpers(struct coresight_device *csdev,
}
/*
- * Helper function to call source_ops(csdev)->disable and also disable the
- * helpers.
- *
- * There is an imbalance between coresight_enable_path() and
- * coresight_disable_path(). Enabling also enables the source's helpers as part
- * of the path, but disabling always skips the first item in the path (which is
- * the source), so sources and their helpers don't get disabled as part of that
- * function and we need the extra step here.
+ * coresight_disable_source() only disables the source, but do nothing for
+ * the associated helpers, which are controlled as part of the path.
*/
void coresight_disable_source(struct coresight_device *csdev, void *data)
{
source_ops(csdev)->disable(csdev, data);
- coresight_disable_helpers(csdev, NULL);
}
EXPORT_SYMBOL_GPL(coresight_disable_source);
@@ -451,7 +444,7 @@ static void coresight_disable_path_from(struct coresight_path *path,
if (!nd)
nd = list_first_entry(&path->path_list, struct coresight_node, link);
- list_for_each_entry_continue(nd, &path->path_list, link) {
+ list_for_each_entry_from(nd, &path->path_list, link) {
csdev = nd->csdev;
type = csdev->type;
@@ -471,12 +464,6 @@ static void coresight_disable_path_from(struct coresight_path *path,
coresight_disable_sink(csdev);
break;
case CORESIGHT_DEV_TYPE_SOURCE:
- /*
- * We skip the first node in the path assuming that it
- * is the source. So we don't expect a source device in
- * the middle of a path.
- */
- WARN_ON(1);
break;
case CORESIGHT_DEV_TYPE_LINK:
parent = list_prev_entry(nd, link)->csdev;
@@ -523,12 +510,16 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
{
int ret = 0;
u32 type;
- struct coresight_node *nd;
+ struct coresight_node *nd, *last;
struct coresight_device *csdev, *parent, *child;
struct coresight_device *source;
source = coresight_get_source(path);
- list_for_each_entry_reverse(nd, &path->path_list, link) {
+
+ last = list_last_entry(&path->path_list, struct coresight_node, link);
+
+ nd = last;
+ list_for_each_entry_from_reverse(nd, &path->path_list, link) {
csdev = nd->csdev;
type = csdev->type;
@@ -582,6 +573,11 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
err_disable_helpers:
coresight_disable_helpers(csdev, path);
err_disable_path:
+ /* No device is actually enabled */
+ if (nd == last)
+ goto out;
+
+ nd = list_next_entry(nd, link);
coresight_disable_path_from(path, nd);
goto out;
}
--
2.34.1
^ permalink raw reply related
* [PATCH v9 13/20] coresight: Use helpers to fetch first and last nodes
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Replace open code with coresight_path_first_node() and
coresight_path_last_node() for fetching the nodes.
Check that the node is not NULL before accessing csdev field.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 739b863d40ced2f939b2063cc4e2aa1c52564c1d..ae0ab074293a8ec473de2e6e3282f62268de38aa 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -106,11 +106,16 @@ EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
static struct coresight_device *coresight_get_source(struct coresight_path *path)
{
struct coresight_device *csdev;
+ struct coresight_node *nd;
if (!path)
return NULL;
- csdev = list_first_entry(&path->path_list, struct coresight_node, link)->csdev;
+ nd = coresight_path_first_node(path);
+ if (!nd)
+ return NULL;
+
+ csdev = nd->csdev;
if (!coresight_is_device_source(csdev))
return NULL;
@@ -644,11 +649,16 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
struct coresight_device *coresight_get_sink(struct coresight_path *path)
{
struct coresight_device *csdev;
+ struct coresight_node *nd;
if (!path)
return NULL;
- csdev = list_last_entry(&path->path_list, struct coresight_node, link)->csdev;
+ nd = coresight_path_last_node(path);
+ if (!nd)
+ return NULL;
+
+ csdev = nd->csdev;
if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
return NULL;
--
2.34.1
^ permalink raw reply related
* [PATCH v9 12/20] coresight: Control path with range
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Add parameters @from and @to for path enabling and disabling, allowing
finer-grained control of a path. The range is [@from..@to], where both
@from and @to are inclusive, introduce coresight_path_nodes_in_order()
to validate the given range if is ordered.
The helpers coresight_path_{first|last}_node() are provided for
conveniently fetching the first and last nodes on the path.
A minor refactoring removes the local variable "source" from
coresight_enable_path_from_to(), deferring reading the source until it
is needed.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 95 ++++++++++++++++++++++------
1 file changed, 77 insertions(+), 18 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index e9fcb82a2abcd52d23a3bed14ca14823dc49df6b..739b863d40ced2f939b2063cc4e2aa1c52564c1d 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -61,6 +61,24 @@ static LIST_HEAD(coresight_dev_idx_list);
static const struct cti_assoc_op *cti_assoc_ops;
+static struct coresight_node *
+coresight_path_first_node(struct coresight_path *path)
+{
+ if (list_empty(&path->path_list))
+ return NULL;
+
+ return list_first_entry(&path->path_list, struct coresight_node, link);
+}
+
+static struct coresight_node *
+coresight_path_last_node(struct coresight_path *path)
+{
+ if (list_empty(&path->path_list))
+ return NULL;
+
+ return list_last_entry(&path->path_list, struct coresight_node, link);
+}
+
void coresight_set_cti_ops(const struct cti_assoc_op *cti_op)
{
cti_assoc_ops = cti_op;
@@ -431,19 +449,41 @@ static struct coresight_path *coresight_get_percpu_local_path(void)
}
/*
- * coresight_disable_path_from : Disable components in the given path beyond
- * @nd in the list. If @nd is NULL, all the components, except the SOURCE are
- * disabled.
+ * Callers must fetch nodes from the path and pass @from and @to to the path
+ * enable/disable functions. Walk the path from @from to locate @to. If @to
+ * is found, it indicates @from and @to are in order. Otherwise, they are out
+ * of order.
*/
-static void coresight_disable_path_from(struct coresight_path *path,
- struct coresight_node *nd)
+static bool coresight_path_nodes_in_order(struct coresight_path *path,
+ struct coresight_node *from,
+ struct coresight_node *to)
+{
+ struct coresight_node *nd;
+
+ if (WARN_ON_ONCE(!from || !to))
+ return false;
+
+ nd = from;
+ list_for_each_entry_from(nd, &path->path_list, link) {
+ if (nd == to)
+ return true;
+ }
+
+ return false;
+}
+
+static void coresight_disable_path_from_to(struct coresight_path *path,
+ struct coresight_node *from,
+ struct coresight_node *to)
{
u32 type;
struct coresight_device *csdev, *parent, *child;
+ struct coresight_node *nd;
- if (!nd)
- nd = list_first_entry(&path->path_list, struct coresight_node, link);
+ if (!coresight_path_nodes_in_order(path, from, to))
+ return;
+ nd = from;
list_for_each_entry_from(nd, &path->path_list, link) {
csdev = nd->csdev;
type = csdev->type;
@@ -477,12 +517,18 @@ static void coresight_disable_path_from(struct coresight_path *path,
/* Disable all helpers adjacent along the path last */
coresight_disable_helpers(csdev, path);
+
+ /* Iterate up to and including @to */
+ if (nd == to)
+ break;
}
}
void coresight_disable_path(struct coresight_path *path)
{
- coresight_disable_path_from(path, NULL);
+ coresight_disable_path_from_to(path,
+ coresight_path_first_node(path),
+ coresight_path_last_node(path));
}
EXPORT_SYMBOL_GPL(coresight_disable_path);
@@ -506,19 +552,20 @@ static int coresight_enable_helpers(struct coresight_device *csdev,
return 0;
}
-int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
+static int coresight_enable_path_from_to(struct coresight_path *path,
+ enum cs_mode mode,
+ struct coresight_node *from,
+ struct coresight_node *to)
{
int ret = 0;
u32 type;
- struct coresight_node *nd, *last;
+ struct coresight_node *nd;
struct coresight_device *csdev, *parent, *child;
- struct coresight_device *source;
- source = coresight_get_source(path);
-
- last = list_last_entry(&path->path_list, struct coresight_node, link);
+ if (!coresight_path_nodes_in_order(path, from, to))
+ return -EINVAL;
- nd = last;
+ nd = to;
list_for_each_entry_from_reverse(nd, &path->path_list, link) {
csdev = nd->csdev;
type = csdev->type;
@@ -558,7 +605,8 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
case CORESIGHT_DEV_TYPE_LINK:
parent = list_prev_entry(nd, link)->csdev;
child = list_next_entry(nd, link)->csdev;
- ret = coresight_enable_link(csdev, parent, child, source);
+ ret = coresight_enable_link(csdev, parent, child,
+ coresight_get_source(path));
if (ret)
goto err_disable_helpers;
break;
@@ -566,6 +614,10 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
ret = -EINVAL;
goto err_disable_helpers;
}
+
+ /* Iterate down to and including @from */
+ if (nd == from)
+ break;
}
out:
@@ -574,14 +626,21 @@ int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
coresight_disable_helpers(csdev, path);
err_disable_path:
/* No device is actually enabled */
- if (nd == last)
+ if (nd == to)
goto out;
nd = list_next_entry(nd, link);
- coresight_disable_path_from(path, nd);
+ coresight_disable_path_from_to(path, nd, to);
goto out;
}
+int coresight_enable_path(struct coresight_path *path, enum cs_mode mode)
+{
+ return coresight_enable_path_from_to(path, mode,
+ coresight_path_first_node(path),
+ coresight_path_last_node(path));
+}
+
struct coresight_device *coresight_get_sink(struct coresight_path *path)
{
struct coresight_device *csdev;
--
2.34.1
^ permalink raw reply related
* [PATCH v9 10/20] coresight: syscfg: Use spinlock to protect active variables
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
To make cscfg_config_sysfs_get_active_cfg() callable in the idle flow, this
commit replaces the mutex with a raw spinlock to protect active variables.
Acquire the raw spinlock with IRQ-safe to avoid lockdep complaint.
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-syscfg.c | 21 ++++++++++-----------
drivers/hwtracing/coresight/coresight-syscfg.h | 2 ++
2 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index d7f5037953d6ba7fb7f83a8012a1abc5ffd0a147..7e070787e18b47bc4be17b0f9821267268600513 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -953,19 +953,21 @@ int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool acti
unsigned long cfg_hash;
int err = 0;
- mutex_lock(&cscfg_mutex);
+ guard(mutex)(&cscfg_mutex);
cfg_hash = (unsigned long)config_desc->event_ea->var;
+ guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock);
+
if (activate) {
/* cannot be a current active value to activate this */
if (cscfg_mgr->sysfs_active_config) {
err = -EBUSY;
- goto exit_unlock;
+ } else {
+ err = _cscfg_activate_config(cfg_hash);
+ if (!err)
+ cscfg_mgr->sysfs_active_config = cfg_hash;
}
- err = _cscfg_activate_config(cfg_hash);
- if (!err)
- cscfg_mgr->sysfs_active_config = cfg_hash;
} else {
/* disable if matching current value */
if (cscfg_mgr->sysfs_active_config == cfg_hash) {
@@ -975,17 +977,14 @@ int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool acti
err = -EINVAL;
}
-exit_unlock:
- mutex_unlock(&cscfg_mutex);
return err;
}
/* set the sysfs preset value */
void cscfg_config_sysfs_set_preset(int preset)
{
- mutex_lock(&cscfg_mutex);
+ guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock);
cscfg_mgr->sysfs_active_preset = preset;
- mutex_unlock(&cscfg_mutex);
}
/*
@@ -994,10 +993,9 @@ void cscfg_config_sysfs_set_preset(int preset)
*/
void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset)
{
- mutex_lock(&cscfg_mutex);
+ guard(raw_spinlock_irqsave)(&cscfg_mgr->sysfs_store_lock);
*preset = cscfg_mgr->sysfs_active_preset;
*cfg_hash = cscfg_mgr->sysfs_active_config;
- mutex_unlock(&cscfg_mutex);
}
EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
@@ -1201,6 +1199,7 @@ static int cscfg_create_device(void)
INIT_LIST_HEAD(&cscfg_mgr->load_order_list);
atomic_set(&cscfg_mgr->sys_active_cnt, 0);
cscfg_mgr->load_state = CSCFG_NONE;
+ raw_spin_lock_init(&cscfg_mgr->sysfs_store_lock);
/* setup the device */
dev = cscfg_device();
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index 66e2db890d8203853a0c3c907b48aa66dd8014e6..658e93c3705f1cb3ba3523d0bc27ac704697dd70 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg.h
@@ -42,6 +42,7 @@ enum cscfg_load_ops {
* @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
* @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
* @load_state: A multi-stage load/unload operation is in progress.
+ * @sysfs_store_lock: Exclusive access sysfs stored variables.
*/
struct cscfg_manager {
struct device dev;
@@ -54,6 +55,7 @@ struct cscfg_manager {
u32 sysfs_active_config;
int sysfs_active_preset;
enum cscfg_load_ops load_state;
+ raw_spinlock_t sysfs_store_lock;
};
/* get reference to dev in cscfg_manager */
--
2.34.1
^ permalink raw reply related
* [PATCH v9 08/20] coresight: etm4x: Hook CPU PM callbacks
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Hook the CPU save and restore callbacks when the self-hosted state is
enabled (pm_save_enable == PARAM_PM_SAVE_SELF_HOSTED) so they can be
invoked by the core layer.
The CPU PM notifier in the ETMv4 driver is no longer needed, remove it
along with its registration and unregistration code.
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 59 +++++-----------------
1 file changed, 13 insertions(+), 46 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 7b91fab9895d7b2a65ebb1161b117d9d3f5fca1b..6d13fa29d178627e3f0918d265634ab63e24803d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1203,7 +1203,7 @@ static const struct coresight_ops_source etm4_source_ops = {
.pause_perf = etm4_pause_perf,
};
-static const struct coresight_ops etm4_cs_ops = {
+static struct coresight_ops etm4_cs_ops = {
.trace_id = coresight_etm_get_trace_id,
.source_ops = &etm4_source_ops,
};
@@ -2003,8 +2003,9 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
return ret;
}
-static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
+static int etm4_cpu_save(struct coresight_device *csdev)
{
+ struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
int ret = 0;
if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED)
@@ -2120,8 +2121,10 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
etm4_cs_lock(drvdata, csa);
}
-static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
+static void etm4_cpu_restore(struct coresight_device *csdev)
{
+ struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED)
return;
@@ -2129,55 +2132,17 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
__etm4_cpu_restore(drvdata);
}
-static int etm4_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
- void *v)
-{
- struct etmv4_drvdata *drvdata;
- unsigned int cpu = smp_processor_id();
-
- if (!etmdrvdata[cpu])
- return NOTIFY_OK;
-
- drvdata = etmdrvdata[cpu];
-
- if (WARN_ON_ONCE(drvdata->cpu != cpu))
- return NOTIFY_BAD;
-
- switch (cmd) {
- case CPU_PM_ENTER:
- if (etm4_cpu_save(drvdata))
- return NOTIFY_BAD;
- break;
- case CPU_PM_EXIT:
- case CPU_PM_ENTER_FAILED:
- etm4_cpu_restore(drvdata);
- break;
- default:
- return NOTIFY_DONE;
- }
-
- return NOTIFY_OK;
-}
-
-static struct notifier_block etm4_cpu_pm_nb = {
- .notifier_call = etm4_cpu_pm_notify,
-};
-
/* Setup PM. Deals with error conditions and counts */
static int __init etm4_pm_setup(void)
{
int ret;
- ret = cpu_pm_register_notifier(&etm4_cpu_pm_nb);
- if (ret)
- return ret;
-
ret = cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
"arm/coresight4:starting",
etm4_starting_cpu, etm4_dying_cpu);
if (ret)
- goto unregister_notifier;
+ return ret;
ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
"arm/coresight4:online",
@@ -2191,15 +2156,11 @@ static int __init etm4_pm_setup(void)
/* failed dyn state - remove others */
cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
-
-unregister_notifier:
- cpu_pm_unregister_notifier(&etm4_cpu_pm_nb);
return ret;
}
static void etm4_pm_clear(void)
{
- cpu_pm_unregister_notifier(&etm4_cpu_pm_nb);
cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
if (hp_online) {
cpuhp_remove_state_nocalls(hp_online);
@@ -2311,6 +2272,12 @@ static int etm4_probe(struct device *dev)
sizeof(struct etmv4_save_state), GFP_KERNEL);
if (!drvdata->save_state)
return -ENOMEM;
+
+ /* Setup CPU PM callbacks */
+ if (!etm4_cs_ops.pm_save_disable) {
+ etm4_cs_ops.pm_save_disable = etm4_cpu_save;
+ etm4_cs_ops.pm_restore_enable = etm4_cpu_restore;
+ }
}
raw_spin_lock_init(&drvdata->spinlock);
--
2.34.1
^ permalink raw reply related
* [PATCH v9 09/20] coresight: etm4x: Remove redundant condition checks in save and restore
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan, Mike Leach
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Since the core layer determines whether context save and restore
operations are needed, performing the same check within the save and
restore callbacks is redundant.
The save and restore flows currently use two-level functions: the first
level handles the condition check, while the second level performs the
low level operations. As the checks are no longer necessary, simplify
the logic into single-level functions.
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 35 +++-------------------
1 file changed, 4 insertions(+), 31 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 6d13fa29d178627e3f0918d265634ab63e24803d..087a32fe34890528c6fa6ada601aeb742f04c41b 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1861,11 +1861,11 @@ static int etm4_dying_cpu(unsigned int cpu)
return 0;
}
-static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
+static int etm4_cpu_save(struct coresight_device *csdev)
{
int i, ret = 0;
struct etmv4_save_state *state;
- struct coresight_device *csdev = drvdata->csdev;
+ struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
struct csdev_access *csa;
struct device *etm_dev;
@@ -2003,26 +2003,10 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
return ret;
}
-static int etm4_cpu_save(struct coresight_device *csdev)
-{
- struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- int ret = 0;
-
- if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED)
- return 0;
-
- /*
- * Save and restore the ETM Trace registers only if
- * the ETM is active.
- */
- if (coresight_get_mode(drvdata->csdev))
- ret = __etm4_cpu_save(drvdata);
- return ret;
-}
-
-static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
+static void etm4_cpu_restore(struct coresight_device *csdev)
{
int i;
+ struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
struct etmv4_save_state *state = drvdata->save_state;
struct csdev_access *csa = &drvdata->csdev->access;
@@ -2121,17 +2105,6 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
etm4_cs_lock(drvdata, csa);
}
-static void etm4_cpu_restore(struct coresight_device *csdev)
-{
- struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
- if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED)
- return;
-
- if (coresight_get_mode(drvdata->csdev))
- __etm4_cpu_restore(drvdata);
-}
-
/* Setup PM. Deals with error conditions and counts */
static int __init etm4_pm_setup(void)
{
--
2.34.1
^ permalink raw reply related
* [PATCH v9 07/20] coresight: Register CPU PM notifier in core layer
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
The current implementation only saves and restores the context for ETM
sources while ignoring the context of links. However, if funnels or
replicators on a linked path resides in a CPU or cluster power domain,
the hardware context for the link will be lost after resuming from low
power states.
To support context management for links during CPU low power modes, a
better way is to implement CPU PM callbacks in the Arm CoreSight core
layer. As the core layer has sufficient information for linked paths,
from tracers to links, which can be used for power management.
As a first step, this patch registers CPU PM notifier in the core layer.
If a source device provides callbacks for saving and restoring context,
these callbacks will be invoked in CPU suspend and resume.
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 98 ++++++++++++++++++++++++++++
include/linux/coresight.h | 2 +
2 files changed, 100 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 74c9f0dd43784dd735885249c1e50fc86f610582..8384d1466b4cc74f7e463388862c58c86b74be79 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -6,6 +6,7 @@
#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/build_bug.h>
+#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
@@ -431,6 +432,11 @@ void coresight_set_percpu_local_path(struct coresight_path *path)
}
EXPORT_SYMBOL_GPL(coresight_set_percpu_local_path);
+static struct coresight_path *coresight_get_percpu_local_path(void)
+{
+ return this_cpu_read(percpu_path);
+}
+
/*
* coresight_disable_path_from : Disable components in the given path beyond
* @nd in the list. If @nd is NULL, all the components, except the SOURCE are
@@ -1647,6 +1653,91 @@ static void coresight_release_device_list(void)
}
}
+static bool coresight_pm_is_needed(struct coresight_path *path)
+{
+ struct coresight_device *csdev;
+
+ if (!path)
+ return false;
+
+ csdev = coresight_get_source(path);
+ if (!csdev)
+ return false;
+
+ /* pm_save_disable() and pm_restore_enable() must be paired */
+ if (!coresight_ops(csdev)->pm_save_disable ||
+ !coresight_ops(csdev)->pm_restore_enable)
+ return false;
+
+ /* Save and restore only if the source is active */
+ if (coresight_get_mode(csdev))
+ return true;
+
+ return false;
+}
+
+static int coresight_pm_device_save(struct coresight_device *csdev)
+{
+ return coresight_ops(csdev)->pm_save_disable(csdev);
+}
+
+static void coresight_pm_device_restore(struct coresight_device *csdev)
+{
+ coresight_ops(csdev)->pm_restore_enable(csdev);
+}
+
+static int coresight_pm_save(struct coresight_path *path)
+{
+ struct coresight_device *source = coresight_get_source(path);
+
+ return coresight_pm_device_save(source);
+}
+
+static void coresight_pm_restore(struct coresight_path *path)
+{
+ struct coresight_device *source = coresight_get_source(path);
+
+ coresight_pm_device_restore(source);
+}
+
+static int coresight_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
+ void *v)
+{
+ struct coresight_path *path = coresight_get_percpu_local_path();
+
+ if (!coresight_pm_is_needed(path))
+ return NOTIFY_OK;
+
+ switch (cmd) {
+ case CPU_PM_ENTER:
+ if (coresight_pm_save(path))
+ return NOTIFY_BAD;
+ break;
+ case CPU_PM_EXIT:
+ case CPU_PM_ENTER_FAILED:
+ coresight_pm_restore(path);
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block coresight_cpu_pm_nb = {
+ .notifier_call = coresight_cpu_pm_notify,
+};
+
+static int __init coresight_pm_setup(void)
+{
+ return cpu_pm_register_notifier(&coresight_cpu_pm_nb);
+}
+
+static void coresight_pm_cleanup(void)
+{
+ cpu_pm_unregister_notifier(&coresight_cpu_pm_nb);
+}
+
const struct bus_type coresight_bustype = {
.name = "coresight",
};
@@ -1701,9 +1792,15 @@ static int __init coresight_init(void)
/* initialise the coresight syscfg API */
ret = cscfg_init();
+ if (ret)
+ goto exit_notifier;
+
+ ret = coresight_pm_setup();
if (!ret)
return 0;
+ cscfg_exit();
+exit_notifier:
atomic_notifier_chain_unregister(&panic_notifier_list,
&coresight_notifier);
exit_perf:
@@ -1715,6 +1812,7 @@ static int __init coresight_init(void)
static void __exit coresight_exit(void)
{
+ coresight_pm_cleanup();
cscfg_exit();
atomic_notifier_chain_unregister(&panic_notifier_list,
&coresight_notifier);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index e9c20ceb9016fa3db256b8c1147c1fd2027b7b0d..5f9d7ea9f5941ab01eb6a084ca558a9417c7727f 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -438,6 +438,8 @@ struct coresight_ops_panic {
struct coresight_ops {
int (*trace_id)(struct coresight_device *csdev, enum cs_mode mode,
struct coresight_device *sink);
+ int (*pm_save_disable)(struct coresight_device *csdev);
+ void (*pm_restore_enable)(struct coresight_device *csdev);
const struct coresight_ops_sink *sink_ops;
const struct coresight_ops_link *link_ops;
const struct coresight_ops_source *source_ops;
--
2.34.1
^ permalink raw reply related
* [PATCH v9 05/20] coresight: etm4x: Set per-CPU path on local CPU
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Introduce the coresight_set_percpu_local_path() helper to set the path
pointer on the local CPU. This helper is used during ETMv4 enable and
disable operations.
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 8 ++++++++
drivers/hwtracing/coresight/coresight-etm4x-core.c | 18 +++++++++++++++---
drivers/hwtracing/coresight/coresight-priv.h | 1 +
3 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 6907da35ed02fa58f8d30f5576627a6ce3b88362..74c9f0dd43784dd735885249c1e50fc86f610582 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -35,6 +35,8 @@
DEFINE_MUTEX(coresight_mutex);
static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
+static DEFINE_PER_CPU(struct coresight_path *, percpu_path);
+
/**
* struct coresight_node - elements of a path, from source to sink
* @csdev: Address of an element.
@@ -423,6 +425,12 @@ int coresight_resume_source(struct coresight_device *csdev)
}
EXPORT_SYMBOL_GPL(coresight_resume_source);
+void coresight_set_percpu_local_path(struct coresight_path *path)
+{
+ this_cpu_write(percpu_path, path);
+}
+EXPORT_SYMBOL_GPL(coresight_set_percpu_local_path);
+
/*
* coresight_disable_path_from : Disable components in the given path beyond
* @nd in the list. If @nd is NULL, all the components, except the SOURCE are
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index a776ebb3b2b0360c99a8dadacfde4c2303dd59d6..7b91fab9895d7b2a65ebb1161b117d9d3f5fca1b 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -234,6 +234,7 @@ void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
struct etm4_enable_arg {
struct etmv4_drvdata *drvdata;
+ struct coresight_path *path;
int rc;
};
@@ -621,8 +622,12 @@ static void etm4_enable_sysfs_smp_call(void *info)
arg->rc = etm4_enable_hw(arg->drvdata);
/* The tracer didn't start */
- if (arg->rc)
+ if (arg->rc) {
coresight_set_mode(csdev, CS_MODE_DISABLED);
+ return;
+ }
+
+ coresight_set_percpu_local_path(arg->path);
}
/*
@@ -890,9 +895,13 @@ static int etm4_enable_perf(struct coresight_device *csdev,
out:
/* Failed to start tracer; roll back to DISABLED mode */
- if (ret)
+ if (ret) {
coresight_set_mode(csdev, CS_MODE_DISABLED);
- return ret;
+ return ret;
+ }
+
+ coresight_set_percpu_local_path(path);
+ return 0;
}
static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
@@ -922,6 +931,7 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa
* ensures that register writes occur when cpu is powered.
*/
arg.drvdata = drvdata;
+ arg.path = path;
ret = smp_call_function_single(drvdata->cpu,
etm4_enable_sysfs_smp_call, &arg, 1);
if (!ret)
@@ -1063,6 +1073,7 @@ static void etm4_disable_sysfs_smp_call(void *info)
etm4_disable_hw(drvdata);
+ coresight_set_percpu_local_path(NULL);
coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
}
@@ -1092,6 +1103,7 @@ static int etm4_disable_perf(struct coresight_device *csdev,
/* TRCVICTLR::SSSTATUS, bit[9] */
filters->ssstatus = (control & BIT(9));
+ coresight_set_percpu_local_path(NULL);
coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
/*
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 1ea882dffd703b2873e41b4ce0c2564d2ce9bbad..ff8a720339deb854ac3b4eb916f49e844f442d34 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -251,5 +251,6 @@ struct coresight_device *coresight_get_percpu_sink(int cpu);
void coresight_disable_source(struct coresight_device *csdev, void *data);
void coresight_pause_source(struct coresight_device *csdev);
int coresight_resume_source(struct coresight_device *csdev);
+void coresight_set_percpu_local_path(struct coresight_path *path);
#endif
--
2.34.1
^ permalink raw reply related
* [PATCH v9 06/20] coresight: etm3x: Set per-CPU path on local CPU
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Set the path pointer on the local CPU during ETMv3 enable and disable
operations.
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-etm3x-core.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index aeeb284abdbe4b6a0960da45baa1138e203f3e3c..46ea66b5cf1985bd7129688f175f6f92372d04ad 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -441,6 +441,7 @@ static int etm_enable_hw(struct etm_drvdata *drvdata)
struct etm_enable_arg {
struct etm_drvdata *drvdata;
+ struct coresight_path *path;
int rc;
};
@@ -462,8 +463,12 @@ static void etm_enable_sysfs_smp_call(void *info)
arg->rc = etm_enable_hw(arg->drvdata);
/* The tracer didn't start */
- if (arg->rc)
+ if (arg->rc) {
coresight_set_mode(csdev, CS_MODE_DISABLED);
+ return;
+ }
+
+ coresight_set_percpu_local_path(arg->path);
}
void etm_release_trace_id(struct etm_drvdata *drvdata)
@@ -492,10 +497,13 @@ static int etm_enable_perf(struct coresight_device *csdev,
ret = etm_enable_hw(drvdata);
/* Failed to start tracer; roll back to DISABLED mode */
- if (ret)
+ if (ret) {
coresight_set_mode(csdev, CS_MODE_DISABLED);
+ return ret;
+ }
- return ret;
+ coresight_set_percpu_local_path(path);
+ return 0;
}
static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
@@ -514,6 +522,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_pat
*/
if (cpu_online(drvdata->cpu)) {
arg.drvdata = drvdata;
+ arg.path = path;
ret = smp_call_function_single(drvdata->cpu,
etm_enable_sysfs_smp_call, &arg, 1);
if (!ret)
@@ -583,6 +592,7 @@ static void etm_disable_sysfs_smp_call(void *info)
etm_disable_hw(drvdata);
+ coresight_set_percpu_local_path(NULL);
coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
}
@@ -607,6 +617,7 @@ static void etm_disable_perf(struct coresight_device *csdev)
CS_LOCK(drvdata->csa.base);
+ coresight_set_percpu_local_path(NULL);
coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
/*
--
2.34.1
^ permalink raw reply related
* [PATCH v9 04/20] coresight: Take hotplug lock in enable_source_store() for Sysfs mode
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan, Mike Leach
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
The hotplug lock is acquired and released in etm{3|4}_disable_sysfs(),
which are low-level functions. This prevents us from a new solution for
hotplug.
Firstly, hotplug callbacks cannot invoke etm{3|4}_disable_sysfs() to
disable the source; otherwise, a deadlock issue occurs. The reason is
that, in the hotplug flow, the kernel acquires the hotplug lock before
calling callbacks. Subsequently, if coresight_disable_source() is
invoked and it calls etm{3|4}_disable_sysfs(), the hotplug lock will be
acquired twice, leading to a double lock issue.
Secondly, when hotplugging a CPU on or off, if we want to manipulate all
components on a path attached to the CPU, we need to maintain atomicity
for the entire path. Otherwise, a race condition may occur with users
setting the same path via the Sysfs knobs, ultimately causing mess
states in CoreSight components.
This patch moves the hotplug locking from etm{3|4}_disable_sysfs() into
enable_source_store(). As a result, when users control the Sysfs knobs,
the whole flow is protected by hotplug locking, ensuring it is mutual
exclusive with hotplug callbacks.
Note, the paired function etm{3|4}_enable_sysfs() does not use hotplug
locking, which is why this patch does not modify it.
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-etm3x-core.c | 8 --------
drivers/hwtracing/coresight/coresight-etm4x-core.c | 9 ---------
drivers/hwtracing/coresight/coresight-sysfs.c | 7 +++++++
3 files changed, 7 insertions(+), 17 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index ab47f69e923fb191b48b82367dce465c79b3a93d..aeeb284abdbe4b6a0960da45baa1138e203f3e3c 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -620,13 +620,6 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
{
struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- /*
- * Taking hotplug lock here protects from clocks getting disabled
- * with tracing being left on (crash scenario) if user disable occurs
- * after cpu online mask indicates the cpu is offline but before the
- * DYING hotplug callback is serviced by the ETM driver.
- */
- cpus_read_lock();
spin_lock(&drvdata->spinlock);
/*
@@ -637,7 +630,6 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
drvdata, 1);
spin_unlock(&drvdata->spinlock);
- cpus_read_unlock();
/*
* we only release trace IDs when resetting sysfs.
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 66a8058098376264d3f8c5815763a75ebffb352e..a776ebb3b2b0360c99a8dadacfde4c2303dd59d6 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1106,13 +1106,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev)
{
struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- /*
- * Taking hotplug lock here protects from clocks getting disabled
- * with tracing being left on (crash scenario) if user disable occurs
- * after cpu online mask indicates the cpu is offline but before the
- * DYING hotplug callback is serviced by the ETM driver.
- */
- cpus_read_lock();
raw_spin_lock(&drvdata->spinlock);
/*
@@ -1126,8 +1119,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev)
cscfg_csdev_disable_active_config(csdev);
- cpus_read_unlock();
-
/*
* we only release trace IDs when resetting sysfs.
* This permits sysfs users to read the trace ID after the trace
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index 3b1e7152dd108408d837c404ce607ba511ca14a6..f398dbfbcb8de0c5a873837c19b3fdcf97b64abe 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -360,6 +360,13 @@ static ssize_t enable_source_store(struct device *dev,
if (ret)
return ret;
+ /*
+ * CoreSight hotplug callbacks in core layer control a activated path
+ * from its source to sink. Taking hotplug lock here protects a race
+ * condition with hotplug callbacks.
+ */
+ guard(cpus_read_lock)();
+
if (val) {
ret = coresight_enable_sysfs(csdev);
if (ret)
--
2.34.1
^ permalink raw reply related
* [PATCH v9 03/20] coresight: Remove .cpu_id() callback from source ops
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
The CPU ID can be fetched directly from the coresight_device structure,
so the .cpu_id() callback is no longer needed.
Remove the .cpu_id() callback from source ops and update callers
accordingly.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 8 ++++----
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
drivers/hwtracing/coresight/coresight-etm3x-core.c | 8 --------
drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 --------
drivers/hwtracing/coresight/coresight-sysfs.c | 4 ++--
include/linux/coresight.h | 3 ---
6 files changed, 7 insertions(+), 26 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 89911fc27128b2bb78c8ba704f2af5a5d4efe83c..6907da35ed02fa58f8d30f5576627a6ce3b88362 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -787,7 +787,7 @@ static int _coresight_build_path(struct coresight_device *csdev,
goto out;
if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) &&
- sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) {
+ sink == per_cpu(csdev_sink, csdev->cpu)) {
if (_coresight_build_path(sink, source, sink, path) == 0) {
found = true;
goto out;
@@ -1014,7 +1014,7 @@ coresight_find_default_sink(struct coresight_device *csdev)
/* look for a default sink if we have not found for this device */
if (!csdev->def_sink) {
if (coresight_is_percpu_source(csdev))
- csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev));
+ csdev->def_sink = per_cpu(csdev_sink, csdev->cpu);
if (!csdev->def_sink)
csdev->def_sink = coresight_find_sink(csdev, &depth);
}
@@ -1752,10 +1752,10 @@ int coresight_etm_get_trace_id(struct coresight_device *csdev, enum cs_mode mode
{
int cpu, trace_id;
- if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE || !source_ops(csdev)->cpu_id)
+ if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
return -EINVAL;
- cpu = source_ops(csdev)->cpu_id(csdev);
+ cpu = csdev->cpu;
switch (mode) {
case CS_MODE_SYSFS:
trace_id = coresight_trace_id_get_cpu_id(cpu);
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index f85dedf89a3f9e85d568ca4c320fa6fa6d9059ff..cae6738e9906c35d291e4b0f3feae37306b95c06 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -824,7 +824,7 @@ static void etm_addr_filters_sync(struct perf_event *event)
int etm_perf_symlink(struct coresight_device *csdev, bool link)
{
char entry[sizeof("cpu9999999")];
- int ret = 0, cpu = source_ops(csdev)->cpu_id(csdev);
+ int ret = 0, cpu = csdev->cpu;
struct device *pmu_dev = etm_pmu.dev;
struct device *cs_dev = &csdev->dev;
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index eb665db1a37d9970f7f55395c0aa23b98a7f3118..ab47f69e923fb191b48b82367dce465c79b3a93d 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -466,13 +466,6 @@ static void etm_enable_sysfs_smp_call(void *info)
coresight_set_mode(csdev, CS_MODE_DISABLED);
}
-static int etm_cpu_id(struct coresight_device *csdev)
-{
- struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
- return drvdata->cpu;
-}
-
void etm_release_trace_id(struct etm_drvdata *drvdata)
{
coresight_trace_id_put_cpu_id(drvdata->cpu);
@@ -684,7 +677,6 @@ static void etm_disable(struct coresight_device *csdev,
}
static const struct coresight_ops_source etm_source_ops = {
- .cpu_id = etm_cpu_id,
.enable = etm_enable,
.disable = etm_disable,
};
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index b1e0254a534027d7ede8591e56be28745d0b9974..66a8058098376264d3f8c5815763a75ebffb352e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -227,13 +227,6 @@ static void etm4_cs_unlock(struct etmv4_drvdata *drvdata,
CS_UNLOCK(csa->base);
}
-static int etm4_cpu_id(struct coresight_device *csdev)
-{
- struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
- return drvdata->cpu;
-}
-
void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
{
coresight_trace_id_put_cpu_id(drvdata->cpu);
@@ -1201,7 +1194,6 @@ static void etm4_pause_perf(struct coresight_device *csdev)
}
static const struct coresight_ops_source etm4_source_ops = {
- .cpu_id = etm4_cpu_id,
.enable = etm4_enable,
.disable = etm4_disable,
.resume_perf = etm4_resume_perf,
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index d2a6ed8bcc74d64dccc735463f14790b4e80d101..3b1e7152dd108408d837c404ce607ba511ca14a6 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -232,7 +232,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
* be a single session per tracer (when working from sysFS)
* a per-cpu variable will do just fine.
*/
- cpu = source_ops(csdev)->cpu_id(csdev);
+ cpu = csdev->cpu;
per_cpu(tracer_path, cpu) = path;
break;
case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
@@ -282,7 +282,7 @@ void coresight_disable_sysfs(struct coresight_device *csdev)
switch (csdev->subtype.source_subtype) {
case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
- cpu = source_ops(csdev)->cpu_id(csdev);
+ cpu = csdev->cpu;
path = per_cpu(tracer_path, cpu);
per_cpu(tracer_path, cpu) = NULL;
break;
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 687190ca11ddeaa83193caa3903a480bac3060d1..e9c20ceb9016fa3db256b8c1147c1fd2027b7b0d 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -395,15 +395,12 @@ struct coresight_ops_link {
/**
* struct coresight_ops_source - basic operations for a source
* Operations available for sources.
- * @cpu_id: returns the value of the CPU number this component
- * is associated to.
* @enable: enables tracing for a source.
* @disable: disables tracing for a source.
* @resume_perf: resumes tracing for a source in perf session.
* @pause_perf: pauses tracing for a source in perf session.
*/
struct coresight_ops_source {
- int (*cpu_id)(struct coresight_device *csdev);
int (*enable)(struct coresight_device *csdev, struct perf_event *event,
enum cs_mode mode, struct coresight_path *path);
void (*disable)(struct coresight_device *csdev,
--
2.34.1
^ permalink raw reply related
* [PATCH v9 01/20] coresight: Extract device init into coresight_init_device()
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
This commit extracts the allocation and initialization of the coresight
device structure into a separate function to make future extensions
easier.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 46f247f73cf64a97b9353b84ba5b76b991676f5f..5452de9367d450de399a2107016c3fddb894fc82 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1322,20 +1322,16 @@ void coresight_release_platform_data(struct device *dev,
devm_kfree(dev, pdata);
}
-struct coresight_device *coresight_register(struct coresight_desc *desc)
+static struct coresight_device *
+coresight_init_device(struct coresight_desc *desc)
{
- int ret;
struct coresight_device *csdev;
- bool registered = false;
csdev = kzalloc_obj(*csdev);
- if (!csdev) {
- ret = -ENOMEM;
- goto err_out;
- }
+ if (!csdev)
+ return ERR_PTR(-ENOMEM);
csdev->pdata = desc->pdata;
-
csdev->type = desc->type;
csdev->subtype = desc->subtype;
csdev->ops = desc->ops;
@@ -1348,6 +1344,21 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
csdev->dev.release = coresight_device_release;
csdev->dev.bus = &coresight_bustype;
+ return csdev;
+}
+
+struct coresight_device *coresight_register(struct coresight_desc *desc)
+{
+ int ret;
+ struct coresight_device *csdev;
+ bool registered = false;
+
+ csdev = coresight_init_device(desc);
+ if (IS_ERR(csdev)) {
+ ret = PTR_ERR(csdev);
+ goto err_out;
+ }
+
if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
raw_spin_lock_init(&csdev->perf_sink_id_map.lock);
--
2.34.1
^ permalink raw reply related
* [PATCH v9 02/20] coresight: Populate CPU ID into coresight_device
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan
In-Reply-To: <20260401-arm_coresight_path_power_management_improvement-v9-0-091d73e44072@arm.com>
Add a new flag CORESIGHT_DESC_CPU_BOUND to indicate components that
are CPU bound. Populate CPU ID into the coresight_device structure;
otherwise, set CPU ID to -1 for non CPU bound devices.
Use the {0} initializer to clear coresight_desc structures to avoid
uninitialized values.
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
drivers/hwtracing/coresight/coresight-catu.c | 2 +-
drivers/hwtracing/coresight/coresight-core.c | 13 +++++++++++++
drivers/hwtracing/coresight/coresight-cti-core.c | 9 ++++++---
drivers/hwtracing/coresight/coresight-etm3x-core.c | 2 ++
drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 ++
drivers/hwtracing/coresight/coresight-trbe.c | 2 ++
include/linux/coresight.h | 8 ++++++++
7 files changed, 34 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
index ce71dcddfca2558eddd625de58a709b151f2e07e..43abe13995cf3c96e70dcf97856872d70f71345a 100644
--- a/drivers/hwtracing/coresight/coresight-catu.c
+++ b/drivers/hwtracing/coresight/coresight-catu.c
@@ -514,7 +514,7 @@ static int __catu_probe(struct device *dev, struct resource *res)
int ret = 0;
u32 dma_mask;
struct catu_drvdata *drvdata;
- struct coresight_desc catu_desc;
+ struct coresight_desc catu_desc = { 0 };
struct coresight_platform_data *pdata = NULL;
void __iomem *base;
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 5452de9367d450de399a2107016c3fddb894fc82..89911fc27128b2bb78c8ba704f2af5a5d4efe83c 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1338,6 +1338,19 @@ coresight_init_device(struct coresight_desc *desc)
csdev->access = desc->access;
csdev->orphan = true;
+ if (desc->flags & CORESIGHT_DESC_CPU_BOUND) {
+ csdev->cpu = desc->cpu;
+ } else {
+ /* A per-CPU source or sink must set CPU_BOUND flag */
+ if (coresight_is_percpu_source(csdev) ||
+ coresight_is_percpu_sink(csdev)) {
+ kfree(csdev);
+ return ERR_PTR(-EINVAL);
+ }
+
+ csdev->cpu = -1;
+ }
+
csdev->dev.type = &coresight_dev_type[desc->type];
csdev->dev.groups = desc->groups;
csdev->dev.parent = desc->dev;
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index 2f4c9362709a90b12a1aeb5016905b7d4474b912..b2c9a4db13b4e5554bca565c17ed299fdfdb30ff 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -659,7 +659,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
void __iomem *base;
struct device *dev = &adev->dev;
struct cti_drvdata *drvdata = NULL;
- struct coresight_desc cti_desc;
+ struct coresight_desc cti_desc = { 0 };
struct coresight_platform_data *pdata = NULL;
struct resource *res = &adev->res;
@@ -702,11 +702,14 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
* eCPU ID. System CTIs will have the name cti_sys<I> where I is an
* index allocated by order of discovery.
*/
- if (drvdata->ctidev.cpu >= 0)
+ if (drvdata->ctidev.cpu >= 0) {
+ cti_desc.cpu = drvdata->ctidev.cpu;
+ cti_desc.flags = CORESIGHT_DESC_CPU_BOUND;
cti_desc.name = devm_kasprintf(dev, GFP_KERNEL, "cti_cpu%d",
drvdata->ctidev.cpu);
- else
+ } else {
cti_desc.name = coresight_alloc_device_name("cti_sys", dev);
+ }
if (!cti_desc.name)
return -ENOMEM;
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index a547a6d2e0bde84748f753e5529d316c4f5e82e2..eb665db1a37d9970f7f55395c0aa23b98a7f3118 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -891,6 +891,8 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
desc.pdata = pdata;
desc.dev = dev;
desc.groups = coresight_etm_groups;
+ desc.cpu = drvdata->cpu;
+ desc.flags = CORESIGHT_DESC_CPU_BOUND;
drvdata->csdev = coresight_register(&desc);
if (IS_ERR(drvdata->csdev))
return PTR_ERR(drvdata->csdev);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index d565a73f0042e3e0b21fcf9cb94009cc25834d3d..b1e0254a534027d7ede8591e56be28745d0b9974 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -2260,6 +2260,8 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
desc.pdata = pdata;
desc.dev = dev;
desc.groups = coresight_etmv4_groups;
+ desc.cpu = drvdata->cpu;
+ desc.flags = CORESIGHT_DESC_CPU_BOUND;
drvdata->csdev = coresight_register(&desc);
if (IS_ERR(drvdata->csdev))
return PTR_ERR(drvdata->csdev);
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 1511f8eb95afb5b4610b8fbdacc8b174b6b08530..14e35b9660d76e47619cc6026b94929b3bb3e02b 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1289,6 +1289,8 @@ static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cp
desc.ops = &arm_trbe_cs_ops;
desc.groups = arm_trbe_groups;
desc.dev = dev;
+ desc.cpu = cpu;
+ desc.flags = CORESIGHT_DESC_CPU_BOUND;
trbe_csdev = coresight_register(&desc);
if (IS_ERR(trbe_csdev))
goto cpu_clear;
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 2131febebee93d609df1aea8534a10898b600be2..687190ca11ddeaa83193caa3903a480bac3060d1 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -141,6 +141,8 @@ struct csdev_access {
.base = (_addr), \
})
+#define CORESIGHT_DESC_CPU_BOUND BIT(0)
+
/**
* struct coresight_desc - description of a component required from drivers
* @type: as defined by @coresight_dev_type.
@@ -153,6 +155,8 @@ struct csdev_access {
* in the component's sysfs sub-directory.
* @name: name for the coresight device, also shown under sysfs.
* @access: Describe access to the device
+ * @flags: The descritpion flags.
+ * @cpu: The CPU this component is affined to.
*/
struct coresight_desc {
enum coresight_dev_type type;
@@ -163,6 +167,8 @@ struct coresight_desc {
const struct attribute_group **groups;
const char *name;
struct csdev_access access;
+ u32 flags;
+ int cpu;
};
/**
@@ -260,6 +266,7 @@ struct coresight_trace_id_map {
* device's spinlock when the coresight_mutex held and mode ==
* CS_MODE_SYSFS. Otherwise it must be accessed from inside the
* spinlock.
+ * @cpu: The CPU this component is affined to (-1 for not CPU bound).
* @orphan: true if the component has connections that haven't been linked.
* @sysfs_sink_activated: 'true' when a sink has been selected for use via sysfs
* by writing a 1 to the 'enable_sink' file. A sink can be
@@ -286,6 +293,7 @@ struct coresight_device {
struct device dev;
atomic_t mode;
int refcnt;
+ int cpu;
bool orphan;
/* sink specific fields */
bool sysfs_sink_activated;
--
2.34.1
^ permalink raw reply related
* [PATCH v9 00/20] CoreSight: Refactor power management for CoreSight path
From: Leo Yan @ 2026-04-01 18:05 UTC (permalink / raw)
To: Suzuki K Poulose, Mike Leach, James Clark, Yeoreum Yun,
Mark Rutland, Will Deacon, Yabin Cui, Keita Morisaki,
Yuanfang Zhang, Greg Kroah-Hartman, Alexander Shishkin,
Tamas Petz
Cc: coresight, linux-arm-kernel, Leo Yan, Mike Leach
This series focuses on CoreSight path power management. The changes can
be divided into four parts for review:
Patches 01 - 04: Refactor the CPU ID storing in csdev, later patches
consume csdev->cpu. Move CPU lock to sysfs layer so
it is safe for later changes.
Patches 05 - 09: Refactor the CPU idle flow with moving common code into
the CoreSight core layer.
Patches 10 - 15: Refactor path enabling and disabling with range, add
path control during CPU idle.
Patches 16 - 17: Support the sink (TRBE) control during CPU idle.
Patches 18 - 20: Move CPU hotplug into the core layer, and fix sysfs
mode for hotplug.
This series is rebased on the coresight-next branch and has been verified
on Juno-r2 (ETM + ETR) and FVP RevC (ETE + TRBE). Built successfully
for armv7 (ARCH=arm).
---
Changes in v9:
- Changed to use per-CPU path pointer with lockless access.
- Removed the change for adding csdev->path, the related refactoring
will be sent separately.
- Re-orged patches to avoid intermediate breakage (sashiko).
- Link to v8: https://lore.kernel.org/r/20260325-arm_coresight_path_power_management_improvement-v8-0-7b1902e18041@arm.com
Changes in v8:
- Moved the "cpu" field in coresight_device for better pack with new
patch 01 (Suzuki).
- Added check if not set CPU for per_cpu_source/per_cpu_sink (Suzuki).
- Renamed spinlock name in syscfg (Suzuki).
- Refactored paired enable and disable path with new patches
10 and 12 (Suzuki).
- Link to v7: https://lore.kernel.org/r/20260320-arm_coresight_path_power_management_improvement-v7-0-327ddd36b58b@arm.com
Changes in v7:
- Added a flag in coresight_desc to indicate CPU bound device (Suzuki).
- Used coresight_mutex to protect per-CPU source pointer (Suzuki).
- Added a spinlock for exclusive access per-CPU source pointer (Suzuki).
- Dropped .pm_is_needed() callback (Suzuki).
- Supported range in path enabling / disabling (Suzuki).
- Gathered test and review tags (Levi / James).
- Link to v6: https://lore.kernel.org/r/20260305-arm_coresight_path_power_management_improvement-v6-0-eff765d211a9@arm.com
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
Leo Yan (19):
coresight: Extract device init into coresight_init_device()
coresight: Populate CPU ID into coresight_device
coresight: Remove .cpu_id() callback from source ops
coresight: Take hotplug lock in enable_source_store() for Sysfs mode
coresight: etm4x: Set per-CPU path on local CPU
coresight: etm3x: Set per-CPU path on local CPU
coresight: Register CPU PM notifier in core layer
coresight: etm4x: Hook CPU PM callbacks
coresight: etm4x: Remove redundant condition checks in save and restore
coresight: syscfg: Use spinlock to protect active variables
coresight: Move source helper disabling to coresight_disable_path()
coresight: Control path with range
coresight: Use helpers to fetch first and last nodes
coresight: Introduce coresight_enable_source() helper
coresight: Control path during CPU idle
coresight: Add PM callbacks for sink device
coresight: sysfs: Increment refcount only for system tracers
coresight: Move CPU hotplug callbacks to core layer
coresight: sysfs: Validate CPU online status for per-CPU sources
Yabin Cui (1):
coresight: trbe: Save and restore state across CPU low power state
drivers/hwtracing/coresight/coresight-catu.c | 2 +-
drivers/hwtracing/coresight/coresight-core.c | 371 ++++++++++++++++++---
drivers/hwtracing/coresight/coresight-cti-core.c | 9 +-
drivers/hwtracing/coresight/coresight-etm-perf.c | 4 +-
drivers/hwtracing/coresight/coresight-etm3x-core.c | 73 +---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 156 ++-------
drivers/hwtracing/coresight/coresight-priv.h | 4 +
drivers/hwtracing/coresight/coresight-syscfg.c | 21 +-
drivers/hwtracing/coresight/coresight-syscfg.h | 2 +
drivers/hwtracing/coresight/coresight-sysfs.c | 50 ++-
drivers/hwtracing/coresight/coresight-trbe.c | 61 +++-
include/linux/coresight.h | 13 +-
12 files changed, 503 insertions(+), 263 deletions(-)
---
base-commit: ec687ba84000d7d50cf243558041f6729d1d8119
change-id: 20251104-arm_coresight_path_power_management_improvement-dab4966f8280
Best regards,
--
Leo Yan <leo.yan@arm.com>
^ permalink raw reply
* RE: Re: Re: Re: Re: [PATCH 1/2] dt-bindings: gpu: mali-valhall-csf: Document i.MX952 support
From: Guangliu Ding @ 2026-04-01 18:03 UTC (permalink / raw)
To: Liviu Dudau
Cc: Daniel Baluta (OSS), Daniel Almeida, Alice Ryhl, Boris Brezillon,
Steven Price, David Airlie, Simona Vetter, Maarten Lankhorst,
Maxime Ripard, Thomas Zimmermann, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Frank Li, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, imx@lists.linux.dev,
linux-arm-kernel@lists.infradead.org, Jiyu Yang
In-Reply-To: <ac1T282yvpdAp_TP@e142607>
Hi Liviu
Thanks a lot for your sharing.
> On Wed, Apr 01, 2026 at 03:59:23PM +0000, Guangliu Ding wrote:
> > Hi Liviu
> >
> > > On Wed, Apr 01, 2026 at 10:31:01AM +0000, Guangliu Ding wrote:
> > > > Hi Liviu
> > > >
> > > > > On Wed, Apr 01, 2026 at 09:43:12AM +0000, Guangliu Ding wrote:
> > > > > > Hi Daniel
> > > > > >
> > > > > > > On 4/1/26 11:48, Guangliu Ding wrote:
> > > > > > > > [You don't often get email from guangliu.ding@nxp.com.
> > > > > > > > Learn why this is important at
> > > > > > > > https://aka.ms/LearnAboutSenderIdentification
> > > > > > > > ]
> > > > > > > >
> > > > > > > > Hi Liviu
> > > > > > > >
> > > > > > > > Thanks for your review. Please refer to my comments below:
> > > > > > > >
> > > > > > > >> On Tue, Mar 31, 2026 at 06:12:38PM +0800, Guangliu Ding
> wrote:
> > > > > > > >>> Add compatible string of Mali G310 GPU on i.MX952 board.
> > > > > > > >>>
> > > > > > > >>> Signed-off-by: Guangliu Ding <guangliu.ding@nxp.com>
> > > > > > > >>> Reviewed-by: Jiyu Yang <jiyu.yang@nxp.com>
> > > > > > > >>> ---
> > > > > > > >>>
> > > > > > > >>> Documentation/devicetree/bindings/gpu/arm,mali-valhall-c
> > > > > > > >>> sf.y
> > > > > > > >>> aml
> > > > > > > >>> | 1
> > > > > > > >>> +
> > > > > > > >>> 1 file changed, 1 insertion(+)
> > > > > > > >>>
> > > > > > > >>> diff --git
> > > > > > > >>> a/Documentation/devicetree/bindings/gpu/arm,mali-valhall
> > > > > > > >>> -csf
> > > > > > > >>> .yam
> > > > > > > >>> l
> > > > > > > >> b/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.
> > > > > > > >> yaml
> > > > > > > >>> index 8eccd4338a2b..6a10843a26e2 100644
> > > > > > > >>> ---
> > > > > > > >>> a/Documentation/devicetree/bindings/gpu/arm,mali-valhall
> > > > > > > >>> -csf
> > > > > > > >>> .yam
> > > > > > > >>> l
> > > > > > > >>> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-val
> > > > > > > >>> +++ hall
> > > > > > > >>> +++ -csf
> > > > > > > >>> +++ .yam
> > > > > > > >>> +++ l
> > > > > > > >>> @@ -20,6 +20,7 @@ properties:
> > > > > > > >>> - enum:
> > > > > > > >>> - mediatek,mt8196-mali
> > > > > > > >>> - nxp,imx95-mali # G310
> > > > > > > >>> + - nxp,imx952-mali # G310
> > > > > > > >> Can you explain why this is needed? Can it not be covered
> > > > > > > >> by the existing compatible?
> > > > > > > > There are functional differences in GPU module (GPUMIX)
> > > > > > > > between
> > > > > > > > i.MX95 and i.MX952. So they cannot be fully covered by a
> > > > > > > > single existing
> > > > > compatible.
> > > > > > > > On i.MX952, The GPU clock is controlled by hardware GPU
> > > > > > > > auto clock-gating mechanism, while the GPU clock is
> > > > > > > > managed explicitly by the
> > > > > > > driver on i.MX95.
> > > > > > > > Because of these behavioral differences, separate
> > > > > > > > compatible strings "nxp,imx95-mali" and "nxp,imx952-mali"
> > > > > > > > are needed to allow the driver to handle the two variants
> > > > > > > > independently and to keep room for future
> > > > > > > divergence.
> > > > > > >
> > > > > > >
> > > > > > > This information should be added in the commit message
> > > > > > > explaining why
> > > > > > >
> > > > > > > the change is needed.
> > > > > > >
> > > > > > >
> > > > > > > But then where is the driver code taking care of these diferences?
> > > > > > >
> > > > > >
> > > > > > Yes. Currently the driver does not require "nxp,imx952-mali" string.
> > > > > > However, when GPU ipa_counters are enabled to calculate the
> > > > > > GPU busy_time/idle_time for GPU DVFS feature, they will
> > > > > > conflict with the hardware GPU auto clock‑gating mechanism,
> > > > > > causing GPU clock to remain
> > > > > always on.
> > > > > > In such cases, ipa_counters need to be disabled so that the
> > > > > > GPU auto clock‑gating mechanism can operate normally, using
> > > "nxp,imx952-mali"
> > > > > string.
> > > > >
> > > > > OK, I understand that you're following guidance from some other
> > > > > senior people on how to upstream patches so you've tried to
> > > > > create the smallest patchset to ensure that it gets reviewed and
> > > > > accepted, but in this case we need to see the other patches as
> > > > > well to decide if your approach is the right one and we do need
> > > > > a separate compatible
> > > string.
> > > > >
> > > > > If enabling GPU ipa_counters causes the clocks to get stuck
> > > > > active, that feels like a hardware bug, so figuring out how to
> > > > > handle that is more important than adding a compatible string.
> > > > >
> > > > > Either add the patch(es) that use the compatible to this series
> > > > > in v2, or put a comment in the commit message on where we can
> > > > > see the
> > > driver changes.
> > > > >
> > > >
> > > > According to discussions with the GPU vendor, this is a hardware
> > > > limitation of Mali-G310 rather than a hardware bug, and it has
> > > > been addressed in newer Mali GPU families.
> > >
> > > I represent the said GPU vendor and I think I know what you're
> > > talking about, but you're taking the wrong approach. All G310s have
> > > a problem where in order to enable access to the ipa_counters the
> > > automatic clock gating gets disabled. So the solution that needs to
> > > be implemented when we add support for IPA_COUNTERs will apply to all
> GPUs, not just MX952.
> >
> > Yes. We have bring-up G310 (V2) GPU on both i.MX95 and i.MX952. And
> > auto clock gating mechanism is firstly introduced in i.MX952 (not supported
> on i.MX95).
> > According to your update, solution needs to be implemented to all GPUs
> > which support auto clock gating mechanism after IPA_COUNTERs are
> supported in the driver, right?
>
> A solution is needed, yes.
>
> > What's your suggestions for 952 gpu dtb node?
>
> There is no IPA_COUNTER use in Panthor at the moment. Unless your DVFS
> controller uses that, I would suggest that we don't introduce a compatible for
> 952 until the time we add support for reading the counters.
>
> It helps if you think in terms of what is already in upstream, rather than mixing
> with the tests that uses kbase code. Does your hardware need extra code in
> upstream in order to function? If so, where is that code? If not, then let's not
> introduce the compatible until we are absolutely sure we need it because we
> have code specific to that SoC. For everything else we will implement an
> architecture fix if needed.
>
Got it. The following compatible string is the correct choice since the GPU on
i.MX952 is fully compatible with the GPU on i.MX95 now.
compatible = "nxp,imx95-mali", "arm,mali-valhall-csf";
I will not mix tests with kbase code in the following upstream patches for panthor driver.
> Best regards,
> Liviu
>
> --
> ====================
> | I would like to |
> | fix the world, |
> | but they're not |
> | giving me the |
> \ source code! /
> ---------------
> ¯\_(ツ)_/¯
^ permalink raw reply
* RE: [EXT] Re: [PATCH 1/2] dt-bindings: gpu: mali-valhall-csf: Document i.MX952 support
From: Guangliu Ding @ 2026-04-01 17:52 UTC (permalink / raw)
To: Krzysztof Kozlowski, Liviu Dudau
Cc: Daniel Baluta (OSS), Daniel Almeida, Alice Ryhl, Boris Brezillon,
Steven Price, David Airlie, Simona Vetter, Maarten Lankhorst,
Maxime Ripard, Thomas Zimmermann, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Frank Li, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, imx@lists.linux.dev,
linux-arm-kernel@lists.infradead.org, Jiyu Yang
In-Reply-To: <562530e9-a607-4dae-9b43-786a3946f795@kernel.org>
Hi Krzysztof
Thank you for the helpful guidance.
After going through the writing binding file and the corresponding
driver/dts code, I have a few updates to share:
> On 01/04/2026 13:27, Guangliu Ding wrote:
> >>>>
> >>>> We discuss only the lack of compatibility in terms of DT, how DT
> >>>> sees compatible devices.
> >>>>
> >>>> And lack of driver code is clear indication that devices are
> >>>> compatible in terms how DT understands it. Feel encouraged to bring
> >>>> actual arguments in commit msgs in the future.
> >>>>
> >>>> Best regards,
> >>>> Krzysztof
> >>>
> >>> So the best approach is only reserve "arm,mali-valhall-csf" for now,
> >>> since currently there is no need for an additional compatible entry
> >>> from a DT
> >> compatibility perspective.
> >>> We can introduce "nxp,imx952-mali" in future commits if hardware or
> >>> driver differences actually require it, and include more detailed
> >>> justification
> >> in the commit message. Right?
> >>
> >> So does that mean you decided not to read writing bindings document?
> >
> > Actually, I followed the compatible string of gpu node in imx952.dtsi
> > during code work since they share the same GPU IP.
> > gpu: gpu@4d900000 {
> > compatible = "nxp,imx95-mali", "arm,mali-valhall-csf"; >
> >
> > Is this line in writing bindings document that you want to mention about?
> > Could you please share more suggestions about the patch optimization?
> > DO add new compatibles in case there are new features or
> bugs.
>
> Please read entire file. I feel like you avoid doing this and just ask me to give
> you shortcut.
>
> There is more than one point from that trivial writing bindings file which
> applies here.
>
> Best regards,
> Krzysztof
DO use fallback compatibles when devices are the same as or a superset of prior implementations.
Under this rule, the following compatible string is correct since the GPU on
i.MX952 is fully compatible with the GPU on i.MX95 now.
compatible = "nxp,imx95-mali", "arm,mali-valhall-csf";
DO add new compatibles in case there are new features or bugs.
Under this rule, the new compatible string is required to support new feature
and the old one must be kept if the GPU auto clock gating mechanism on i.MX952
needs additional fixes after ipa_counters are enabled in the driver.
compatible = "nxp,imx952-mali", "nxp,imx95-mali", "arm,mali-valhall-csf";
^ permalink raw reply
* Re: [PATCH 12/33] rust: macros: update `extract_if` MSRV TODO comment
From: Miguel Ojeda @ 2026-04-01 17:45 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHVSX66206Y.3E7I9QUNTCJ8I@garyguo.net>
On Wed, Apr 1, 2026 at 4:18 PM Gary Guo <gary@garyguo.net> wrote:
>
> When I write the comment the intention is to enable the unstable feature and
> switch.
Yeah, that is what I meant as the alternative in the commit message.
I am OK with either.
(By the way, I wondered why you mentioned 1.85 in the comment, I guess
it was supposed to be 1.86 instead originally, i.e. "above" as in >
1.86)
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH 09/33] rust: kbuild: make `--remap-path-prefix` workaround conditional
From: Miguel Ojeda @ 2026-04-01 17:39 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHVLQAOMLWB.3FHHSYKNM5TNP@garyguo.net>
On Wed, Apr 1, 2026 at 4:08 PM Gary Guo <gary@garyguo.net> wrote:
>
> Okay, I see what the comments mean now. Perhaps squash this to the previous
> commit?
This one was mostly to ensure the workaround was not needed anymore,
i.e. it is more "optional" than the other.
In fact, we may want to just not have neither of the patches, i.e. we
could just remove the workaround given the timelines of the branches
-- please see my reply on the previous one on this.
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH] iommu: Always fill in gather when unmapping
From: Jason Gunthorpe @ 2026-04-01 17:36 UTC (permalink / raw)
To: Robin Murphy
Cc: Alexandre Ghiti, AngeloGioacchino Del Regno, Albert Ou, asahi,
Baolin Wang, iommu, Janne Grunau, Jernej Skrabec, Joerg Roedel,
Jean-Philippe Brucker, linux-arm-kernel, linux-mediatek,
linux-riscv, linux-sunxi, Matthias Brugger, Neal Gompa,
Orson Zhai, Palmer Dabbelt, Paul Walmsley, Samuel Holland,
Sven Peter, virtualization, Chen-Yu Tsai, Will Deacon, Yong Wu,
Chunyan Zhang, Lu Baolu, Janusz Krzysztofik, Joerg Roedel,
Jon Hunter, patches, Samiullah Khawaja, stable, Vasant Hegde
In-Reply-To: <ee2c2044-e329-4cdd-ac35-9365824d3677@arm.com>
On Wed, Apr 01, 2026 at 05:33:28PM +0100, Robin Murphy wrote:
> > io-pgtable might have intended to allow the driver to choose between
> > gather or immediate flush because it passed gather to
> > ops->tlb_add_page(), however no driver does anything with it.
>
> Apart from arm-smmu-v3...
Bah, I did my research on the wrong tree and missed this.
> > mtk uses io-pgtable-arm-v7s but added the range to the gather in the
> > unmap callback. Move this into the io-pgtable-arm unmap itself. That
> > will fix all the armv7 using drivers (arm-smmu, qcom_iommu,
> > ipmmu-vmsa).
>
> io-pgtable-arm-v7s != io-pgtable-arm. You're *breaking* MTK (and failing
> to fix the other v7s user, which is MSM).
I was very confused what you were talking about, but I see now that
the hunk adding iommu_iotlb_gather_add_range() to v7 got lost somehow!
@@ -596,6 +596,9 @@ static size_t __arm_v7s_unmap(struct arm_v7s_io_pgtable *data,
__arm_v7s_set_pte(ptep, 0, num_entries, &iop->cfg);
+ if (!iommu_iotlb_gather_queued(gather))
+ iommu_iotlb_gather_add_range(gather, iova, size);
+
for (i = 0; i < num_entries; i++) {
if (ARM_V7S_PTE_IS_TABLE(pte[i], lvl)) {
/* Also flush any partial walks */
> > arm-smmu uses both ARM_V7S and ARM LPAE formats. The LPAE formats
> > already have the gather population because SMMUv3 requires it, so it
> > becomes consistent.
>
> Huh? arm-smmu-v3 invokes iommu_iotlb_gather_add_page() itself, because
> arm-smmu-v3 uses gathers
Yeah, I missed this whole bit, it needs some changes.
> Invoking add range before add_page will end up defeating the
> iommu_iotlb_gather_is_disjoint() check and making SMMUv3
> overinvalidate between disjoint ranges.
Right, that flow needs fixing.
> I guess now I remember why we weren't validating gathers in core code
> before :(
My point is not filling the gather is a micro-optimization that
benefits a few drivers. I think it is so small compared to an IOTLB
flush that it isn't worth worrying about.
So, I'd like to make everything the same and populate the gather
correctly in all flows. I'll fix the SMMUv3 thing and lets look again,
this patch is not so scary to make me think we shouldn't do that.
> @@ -2714,6 +2714,10 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
> pr_debug("unmapped: iova 0x%lx size 0x%zx\n",
> iova, unmapped_page);
> + /* If the driver itself isn't using the gather, mark it used */
> + if (iotlb_gather->end <= iotlb_gather->start)
> + iommu_iotlb_gather_add_range(&iotlb_gather, iova, unmapped_page);
The gathers can be joined across unmaps and now we are inviting subtly
ill-formed gathers as only the first unmap will get included.
We do have error cases where the gather is legitimately empty, and
this would squash that, it probably needs to check unmapped_page for 0
too, at least.
Thanks,
Jason
^ permalink raw reply
* Re: [PATCH 08/33] rust: kbuild: simplify `--remap-path-prefix` workaround
From: Miguel Ojeda @ 2026-04-01 17:36 UTC (permalink / raw)
To: Gary Guo
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <DHHVEPJHLGDW.1E6KDP9BUFG5U@garyguo.net>
On Wed, Apr 1, 2026 at 3:59 PM Gary Guo <gary@garyguo.net> wrote:
>
> I'm not sure that I parse this. You do remove the filter-out completely below?
(I see you saw the other commit)
> Looks like this is going to conflict with rust-fixes (which adds the
> --remap-path-scope). Perhaps worth doing a back merge?
It would be only a couple lines conflicting, so it should be fine.
Having said that, when I was doing this, I wondered if we should even
consider keeping the workaround. In other words, locally for
`rust-next`, the "normal" commit would be to remove the workaround
entirely because there the flag doesn't exist to begin with (i.e. the
workaround should have been removed back when the revert landed).
Then, when conflict happens in linux-next, we can just keep the
addition of the flag from your commit -- the rest can say as-is, i.e.
no workaround needed, because you only enable both flags in a version
(1.95.0) where there is no need for the workaround (which was for <
1.87.0).
It is also why I added the second commit here, i.e. the "make it
conditional", because I was testing that indeed we didn't need the
workaround anymore.
So it may just simpler to do that. What I thought was that perhaps the
workaround is good even if we ourselves don't pass the flag, e.g.
someone else may be passing it. But the chances are very low,
restricted to a couple versions, and the error is obvious and at build
time anyway.
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH] arch/arm: Drop CONFIG_FIRMWARE_EDID from defconfig files
From: Kevin Hilman @ 2026-04-01 17:33 UTC (permalink / raw)
To: Thomas Zimmermann, linux, aaro.koskinen, jmkrzyszt, tony, andreas,
rogerq, arnd
Cc: linux-arm-kernel, linux-kernel, linux-omap, soc, linux-fbdev,
dri-devel, Thomas Zimmermann
In-Reply-To: <20260401082533.214103-1-tzimmermann@suse.de>
Thomas Zimmermann <tzimmermann@suse.de> writes:
> CONFIG_FIRMWARE_EDID=y depends on X86 or EFI_GENERIC_STUB. Neither is
> true here, so drop the lines from the defconfig files.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/arm/configs/davinci_all_defconfig | 1 -
> arch/arm/configs/omap1_defconfig | 1 -
> arch/arm/configs/omap2plus_defconfig | 1 -
For omap*_defconfig:
Acked-by: Kevin Hilman (TI) <khilman@baylibre.com>
Kevin
^ permalink raw reply
* Re: [PATCH] KVM: arm64: Pass a 64bit function-id in the SMC handlers
From: Sebastian Ene @ 2026-04-01 17:21 UTC (permalink / raw)
To: Marc Zyngier
Cc: catalin.marinas, kvmarm, linux-arm-kernel, linux-kernel,
android-kvm, joey.gouly, korneld, mrigendra.chaubey, oupton,
perlarsen, suzuki.poulose, will, yuzenghui
In-Reply-To: <86341e4to0.wl-maz@kernel.org>
On Wed, Apr 01, 2026 at 03:55:11PM +0100, Marc Zyngier wrote:
> On Wed, 01 Apr 2026 13:32:01 +0100,
> Sebastian Ene <sebastianene@google.com> wrote:
> >
> > Make the SMC handlers accept a 64bit value for the function-id to keep
> > it uniform with the rest of the code and prevent a u64 -> u32 -> u64
> > conversion as it currently happens when we handle PSCI.
>
> That seems overly creative. The spec says (2.5, from ARM DEN 0028 1.6
> G):
I'm not plannig to be *overly creative*. Thanks for pointing out the ARM
spec.
>
> "The Function Identifier is passed on W0 on every SMC and HVC
> call. Its 32-bit integer value indicates which function is being
> requested by the caller. It is always passed as the first argument to
> every SMC or HVC call in R0 or W0."
>
> which indicates that it is *always* a 32bit value.
>
> So if you have a 64bit value somewhere, *that* should be fixed, not
> propagated arbitrarily.
If you have a non SMCCC call that happen to have the first 32-bits of
the function-id matching either PSCI or FF-A you will end up handling
them instead of forwarding it to Trustzone because func_id is declared as:
DECLARE_REG(u64, func_id, host_ctxt, 0);
>
> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
Thanks,
Sebastian
^ permalink raw reply
* Re: Re: Re: Re: [PATCH 1/2] dt-bindings: gpu: mali-valhall-csf: Document i.MX952 support
From: Liviu Dudau @ 2026-04-01 17:20 UTC (permalink / raw)
To: Guangliu Ding
Cc: Daniel Baluta (OSS), Daniel Almeida, Alice Ryhl, Boris Brezillon,
Steven Price, David Airlie, Simona Vetter, Maarten Lankhorst,
Maxime Ripard, Thomas Zimmermann, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Frank Li, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, imx@lists.linux.dev,
linux-arm-kernel@lists.infradead.org, Jiyu Yang
In-Reply-To: <AM0PR04MB4707604AF2C445971C7474EFF350A@AM0PR04MB4707.eurprd04.prod.outlook.com>
On Wed, Apr 01, 2026 at 03:59:23PM +0000, Guangliu Ding wrote:
> Hi Liviu
>
> > On Wed, Apr 01, 2026 at 10:31:01AM +0000, Guangliu Ding wrote:
> > > Hi Liviu
> > >
> > > > On Wed, Apr 01, 2026 at 09:43:12AM +0000, Guangliu Ding wrote:
> > > > > Hi Daniel
> > > > >
> > > > > > On 4/1/26 11:48, Guangliu Ding wrote:
> > > > > > > [You don't often get email from guangliu.ding@nxp.com. Learn
> > > > > > > why this is important at
> > > > > > > https://aka.ms/LearnAboutSenderIdentification
> > > > > > > ]
> > > > > > >
> > > > > > > Hi Liviu
> > > > > > >
> > > > > > > Thanks for your review. Please refer to my comments below:
> > > > > > >
> > > > > > >> On Tue, Mar 31, 2026 at 06:12:38PM +0800, Guangliu Ding wrote:
> > > > > > >>> Add compatible string of Mali G310 GPU on i.MX952 board.
> > > > > > >>>
> > > > > > >>> Signed-off-by: Guangliu Ding <guangliu.ding@nxp.com>
> > > > > > >>> Reviewed-by: Jiyu Yang <jiyu.yang@nxp.com>
> > > > > > >>> ---
> > > > > > >>>
> > > > > > >>> Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.y
> > > > > > >>> aml
> > > > > > >>> | 1
> > > > > > >>> +
> > > > > > >>> 1 file changed, 1 insertion(+)
> > > > > > >>>
> > > > > > >>> diff --git
> > > > > > >>> a/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf
> > > > > > >>> .yam
> > > > > > >>> l
> > > > > > >> b/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf.
> > > > > > >> yaml
> > > > > > >>> index 8eccd4338a2b..6a10843a26e2 100644
> > > > > > >>> ---
> > > > > > >>> a/Documentation/devicetree/bindings/gpu/arm,mali-valhall-csf
> > > > > > >>> .yam
> > > > > > >>> l
> > > > > > >>> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-valhall
> > > > > > >>> +++ -csf
> > > > > > >>> +++ .yam
> > > > > > >>> +++ l
> > > > > > >>> @@ -20,6 +20,7 @@ properties:
> > > > > > >>> - enum:
> > > > > > >>> - mediatek,mt8196-mali
> > > > > > >>> - nxp,imx95-mali # G310
> > > > > > >>> + - nxp,imx952-mali # G310
> > > > > > >> Can you explain why this is needed? Can it not be covered by
> > > > > > >> the existing compatible?
> > > > > > > There are functional differences in GPU module (GPUMIX)
> > > > > > > between
> > > > > > > i.MX95 and i.MX952. So they cannot be fully covered by a
> > > > > > > single existing
> > > > compatible.
> > > > > > > On i.MX952, The GPU clock is controlled by hardware GPU auto
> > > > > > > clock-gating mechanism, while the GPU clock is managed
> > > > > > > explicitly by the
> > > > > > driver on i.MX95.
> > > > > > > Because of these behavioral differences, separate compatible
> > > > > > > strings "nxp,imx95-mali" and "nxp,imx952-mali" are needed to
> > > > > > > allow the driver to handle the two variants independently and
> > > > > > > to keep room for future
> > > > > > divergence.
> > > > > >
> > > > > >
> > > > > > This information should be added in the commit message
> > > > > > explaining why
> > > > > >
> > > > > > the change is needed.
> > > > > >
> > > > > >
> > > > > > But then where is the driver code taking care of these diferences?
> > > > > >
> > > > >
> > > > > Yes. Currently the driver does not require "nxp,imx952-mali" string.
> > > > > However, when GPU ipa_counters are enabled to calculate the GPU
> > > > > busy_time/idle_time for GPU DVFS feature, they will conflict with
> > > > > the hardware GPU auto clock‑gating mechanism, causing GPU clock to
> > > > > remain
> > > > always on.
> > > > > In such cases, ipa_counters need to be disabled so that the GPU
> > > > > auto clock‑gating mechanism can operate normally, using
> > "nxp,imx952-mali"
> > > > string.
> > > >
> > > > OK, I understand that you're following guidance from some other
> > > > senior people on how to upstream patches so you've tried to create
> > > > the smallest patchset to ensure that it gets reviewed and accepted,
> > > > but in this case we need to see the other patches as well to decide
> > > > if your approach is the right one and we do need a separate compatible
> > string.
> > > >
> > > > If enabling GPU ipa_counters causes the clocks to get stuck active,
> > > > that feels like a hardware bug, so figuring out how to handle that
> > > > is more important than adding a compatible string.
> > > >
> > > > Either add the patch(es) that use the compatible to this series in
> > > > v2, or put a comment in the commit message on where we can see the
> > driver changes.
> > > >
> > >
> > > According to discussions with the GPU vendor, this is a hardware
> > > limitation of Mali-G310 rather than a hardware bug, and it has been
> > > addressed in newer Mali GPU families.
> >
> > I represent the said GPU vendor and I think I know what you're talking about,
> > but you're taking the wrong approach. All G310s have a problem where in
> > order to enable access to the ipa_counters the automatic clock gating gets
> > disabled. So the solution that needs to be implemented when we add support
> > for IPA_COUNTERs will apply to all GPUs, not just MX952.
>
> Yes. We have bring-up G310 (V2) GPU on both i.MX95 and i.MX952. And auto clock
> gating mechanism is firstly introduced in i.MX952 (not supported on i.MX95).
> According to your update, solution needs to be implemented to all GPUs which support
> auto clock gating mechanism after IPA_COUNTERs are supported in the driver, right?
A solution is needed, yes.
> What's your suggestions for 952 gpu dtb node?
There is no IPA_COUNTER use in Panthor at the moment. Unless your DVFS controller uses
that, I would suggest that we don't introduce a compatible for 952 until the time we
add support for reading the counters.
It helps if you think in terms of what is already in upstream, rather than mixing with
the tests that uses kbase code. Does your hardware need extra code in upstream in order
to function? If so, where is that code? If not, then let's not introduce the compatible
until we are absolutely sure we need it because we have code specific to that SoC. For
everything else we will implement an architecture fix if needed.
Best regards,
Liviu
--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
¯\_(ツ)_/¯
^ permalink raw reply
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